1. Field of the Invention
This invention relates generally to wireless communications and wireless mobile communication devices. In particular, the invention relates to general Extensible Markup Language (XML) support for wireless communication devices.
2. Description of the State of the Art
XML is quickly becoming one of the most common schemes for exchanging data between different computer systems. For transfer over wireless or other narrowband communication systems however, an efficient encoding scheme is required to reduce the size of XML documents for transmission. Perhaps the most popular encoding scheme for preparing XML documents for wireless transmission is Wireless Application Protocol (WAP) Binary XML, or WBXML. WBXML relies on token tables or code books to encode and decode XML. The WBXML specification uses the term “code page” to signify a set of token to tag equivalences. A code page can have no more than 256 entries, so there may be several code pages. The term “code book” is used herein to denote a set of one or more code pages. A code book is therefore a set of lookup tables that maps between XML tags or attributes and their corresponding tokenized equivalents.
Known XML solutions for wireless communication systems use two copies of token tables. One copy is typically embedded at an information gateway, a server or other information source for transcoding or tokenizing from XML to WBXML, whereas another copy is embedded in a mobile communication device side of software application code, which parses and/or decodes the tokenized WBXML. In fact, most known WBXML client software applications have the encoding scheme embedded in the parser. This works well if the encoding scheme is well known. However, for new XML dialects, there is no known encoding scheme. A software application developer that wishes to use a new XML dialect must invent an encoding scheme and/or create both a transcoder to do the encoding and a parser for the client software application.
In such systems, a mobile communication device or possibly software applications installed on such a device must know how an XML document was encoded, that is, which token table was used, by a WBXML encoder in order to process a received WBXML document. This means that an XML application in the mobile communication devices is normally configured for a specific type of XML corresponding to an encoding scheme used at a server or gateway. When an XML processor is implemented in computer software code for example, encoding schema is typically embedded into the software code, such that every time a new XML document type is received, both server software code and mobile communication device software code must be modified accordingly, which is costly, time consuming, and error-prone, particularly if different entities are responsible for server operations and mobile communication devices and applications. Further, if a WBXML parser receives a WBXML document generated from an XML document type that it has never previously processed and the code book for that particular XML document type is not embedded in the decoder or parser or a mobile communication device in which the decoder or parser is implemented, then the device and any software applications on the device are unable to process the WBXML document.
Therefore, there remains a need for a system and method for universal XML support on mobile communication devices which is not restricted to any particular encoding scheme so that XML-enabled applications are independent of a particular XML type and its encoding schema.
There remains a related need for a system and method for processing XML documents of any type.
There remains a further need for a system and method for supporting XML on mobile communication devices which support new XML document types without need to change the software code on the devices.